Note: Descriptions are shown in the official language in which they were submitted.
This invelltion rela-tes to solar ener~y collectors of the
li~uid heat-excllange type.
Collectors of the liquid heat-exchange type generally
comprise a housing having an absorber located therein. A
plurality of conduits are connected between upper and lower
headers and in intimate heat-exchange relationship with the
absorber. The headers of each collector may be connected to
common manifolds or other conduits, or directly to the headers
of adjacent collectors.
l~llen several of the collectors in an array are connected
in a parallel flow arrangement for liquid in the conduits,
a flow condition develops which creates non-uniform output
temperatures in the collector array. The temperature of the
liquid from the collectors in the center of the array is
generally substantially higher than the temperature of the
liquid from collectors at the ends of the array. This indi-
cates that less liquid is flowing through the center collec-
tors than through the end collectors, and therefore less total
heat is transferred to the liquid in the center collectors,
not~ithstanding the higher temperatures. The non-uniform fluid
flow is due to the fact that both headers are of constant
dimension from one end of the collector array to the other.
This causes a condition of relatively low flow resistance
through the headers near the inlet and outlet ends of the array
and relatively high flow resistance through the headers at
the center of the array. The greater the resistance to fluid
flow the lower the flow rate. The lower the flow rate of a
fluid through a collector the higher the outlet temperature of
the collector.
The non-uniform fluid flow could be counteracted by
providing appropriately tapered head~rs or manifolds. How-
ever, this is not a practical solution from the standpoint
of manufacturing expense.
Another solution is to place balanciny valves
between the connections of the headers of each collector,
or between the respective manifolds and the collectors.
Such valves are, however, expensive and require large spa-
cing between adjacent collectors, reducing the area of
collector coverage where the area availabl~ to collect sun-
light is limited. Furthermore, the individual valves eachrequire proper adjustment, which can take a considerable
amount of time and is often not done properly by installers.
The present invention can provide a new and im-
proved means for regulating the flow of liquid through
manifolds or headers of a collector array, facilitating a
shortened coupling between the headers and manifolds or
the headers of adjacent collectors. The invention can fur-
ther provide means for draining liquids from the system
and/or bleeding air from the system, depending on the posi-
tion of the means in the input headers or the output headers.
According to the invention, there is provided amethod to facilitate the balanced flow of liquid through an
array of solar collectors of the heat exchange type, each
collector having inlet and outlet headers with conduits ex-
tending therebetween, comprising connecting said inlet
headers into a liquid input line so as to establish connec-
tion between each of said headers and a liquid input by
means of coupling members each connected to a connection
on an inlet header and another part of the input line so as
to complete a liquid path through a passageway in the coup-
ling member between the liquid input and said inlet headers,
connecting said outlet headers into a liquid outlet line
establishing a connection between said headers and a liquid
~3~
outlet by means of coupling members each connected to a
connection on an outlet header and another part of the out-
let line so as to complete a liquid path through a passage-
way in the coupliny member between the liquid outlet and
said outlet headers, at least some of said coupling members
having integral baffles forming an orifice adapted to re-
strict the flow through its passageway, and selecting the
sizes of the orifices in said coupling members so that they
change progressively from end to end of the array to balance
the flow of liquid through the collectors of the array.
The invention also extends to solar collector
arrays so constructed and to the coupling members used
therein. The coupling members may further include a normal-
ly closed bleeder vent which can be used either to bleed
air or drain liquid - -
-3a-
1.8~
from tile system depending on whether it is directed upwardly
or down~ardly.
In a second embodiment, the member is resilient and
includes an accordion fold to permit the headers to expand
or contract. In this embodiment the bleed vent is optional.
An object of this invention is to provide a new and
improved apparatus for regulating the flow of liquid in an
array of parallel liquid heat-exchange solar energy collectors.
Another object of the invention is to provide a new and
improved header or manifold coupling member for collectors
of the type described which functions to regulate the flow
of liquid to the respective collectors and facilitates re-
ducing the spacing between collectors in the array.
A further object of the invention is to provide a new
and improved coupling member of the type described which
also permits bleeding and draining of the system.
The features of the invention which are believed to be
novel are particularly pointed out and distinctly claimed
in the concluding portion of this specification. The inven-
tiOll, however, both as to its organization and operation
together with further objects and advantages thereo~ may
best be appreciated by reference to the following detailed
description taken in conjunction with the drawings, wherein:
FIG. 1 is a plan view of a six collector array with the
covers of three collectors partially cut away;
FIG. 2 is a view partially in section seen in the plane
of lines 2-2 of Fig. l;
FIG. 3 is a sectional view seen in the plane o~ lines
3-3 of Fig. l;
FIG. 4 is an end view of a coupling member for coupling
- 4
3,5
the headers of adjacent collectors together;
FIG. 5 is a sectional view seen in the plane of lines 5-5
of Fig. 4;
FIGS. 6, 7 and 8 are views of the connector of Fig. 4
showing progressively lar~er areas of the internal baffle thereof
removed;
FIG. 9 is a schematic diagram of the collector array of
Fig. 1 showing the headers and the coupling member therebetween;
FIG. 10 is a side sectional view of a second embodiment of
the invention; and
FIG. 11 is a schematic diagram of a collector array between
manifolds and having coupling members between the manifolds and
the collectors.
An array 10 of collectors includes a plurality of individual
collectors. As exemplified in Fig. 1, array 10 includes six
collectors 11-16. Each collector comprises a housing 17 including
side walls 18 and 19, end walls 20 and 21, a base 22 and trans-
parent cover 23. Within the housing is situated an absorber 24
resting on insulation 25. Extending inside the collectors along
the lower and upper ends of the absorber are lower and upper
headers 26 and 27. A plurality of conduits 28 extend beween
headers 26 and 27 in intimate heat-exchange relationship with
absorber 24. The headers 26 and 27 are exemplified as being con-
nected to headers of adjacent collectors to form inlet and outlet
lines. Each header may alternatively be connected to manifolds
(see Fig. 11) to form inlet and outlet lines. The ends of the
headers in the extreme upstream and downstream collectors are
terminated by caps 29 through 32. The lower header of the upstream
collector 11 includes a liquid inlet 33 and the downstream
i'9 ~
collector 16 upper header 27 includes an outlet 34. The ou-tlet
and inlet are similar in construction. The outlet is exemplified
in Fig. 3, and hereinafter described.
As exemplified in Fig. 2, each collec~or includes a housing
shown as being of the type disclosed in Canadian Patent No.
1,093,408 issued to the present applicant on January 13, 1981.
Side wall 19 includes an inwardly directed ledge 35 ~or sup-
porting transparent cover member 23. Tlle cover member is clamped
between support ledge 35 and a cap 36, which is afixed to side
wall 19 by means of scraws extending into the trough formed by
vertical members 37 and 38 and horizontal member 39. A flashing
reglet 40 provides a seat for flashing (not shown) extending
between adjacent collectors.
Header 27 extends through an aperture 41 in side wall 19.
An adapter member 42 is seated in aperture 41 and carries therein
an annulus of sealing member 43 which surrounds header 27 to
insulate it from contact with the housing frame and prevent cooler
ambient air from leaking into the collector.
Header 27 is provided with end connections 44 swaged to a
sli~htly enlarged diameter. The enlarged ends receive a coupling
member 45 described more fully hereinafter. Headers 26 are also
provided with enlarged end connections to receive a coupling member 45.
An arrangement of the outlet 34 of the collector array is
exemplified in Fig. 3. Header 27 terminates short of end wall 19
and is received within one arm of a tee-shaped fitting 46. The
other arm of tee 46 received a cap 47. The lower leg of tee 46
received a fitting 48 adapted to receive a conduit (not shown) to
a heat storage or heat utilization device, depending on the purpose
of the heating system. The fitting 48 extends through base 22, the
base including an
--6--
adapter 49 extending into the collector. ~n annular sealing
member 50 insulates tee 46 and fitting 48 from the base 22.
As exemplified in Figs. 4 an~ 5, coupling member 45
includes a hollow cylindrical body 51 derining a passageway
51a and havillg an internal baffle 52 extending thereacross.
Varying areas of baffle 52 are removed to define orifices
having sizes depending on the location of a particular coup-
ling member 45 in the array. A bleed vent 53 extends from the
body, covered by cap 54 threaded thereon. The bleed vent 53
preferably extends from the center of the cylindrical body.
A collar 55 extends around the center of the body to provide
~ ~,,6~ co7~ccf~'~,7~i
uniform separation for the opposing ~K~ of the headers con-
nected thereto, and to facilitate soldering the ends to
member 45.
Figs. 6, 7 and 8 exemplify three coupling members 45a,
45b and 45c in which differing areas of baffle 52 have been
removed.
Fig. 6 exemplifies a coupling member 45a in which a small
area of baffle 52 has been removed to provide a small orifice
20 52a. Coupling member 45b has a larger orifice 52b in its
baffle and coupling member 45c, shown in Fig. 8, has a still
larger orifice 52c in its baffle 52. It is apparent that flow
through coupling member 45a will be restricted to a greater
extent than through coupling member 45b, and flow through
coupling member 45c will be restricted the least.
The array 10, as schematically exemplified in Fig. 9, has
coupling member 45c coupling headers 26 of collectors 11 and
12, coupling member 45b coupling headers 26 of collectors 13
and 14, and coupling member 45a coupling headers 26 of collec-
tors 15 and 16. The inlet 33 is situated in headers 26 of
3~
upstream collector 11. The heat-exchange conduits 28 of the
individual eollectors are not shown in Fig. 9.
Coupling member 45a serves to eouple ~he headers 27 of eollee-
tors 11 and 12, coupling member 45b couples headers 27 of collec-
tors 13 and 14 and coupling member 45c couples headers 27 of
collectors 15 and 16. Outlet 34 is situated in header 27 of down-
stream eollector 16.
The couplin~ between the other header ends may be a coupling
disclosed in our Canadian Patent Application Serial No. 321,191,
filed February 9, 1977, arranged to eompensate for header expansion
and contraetion.
In operation, the liquid entering from inlet 33 into headers
26 eneounters increased resistanee to flow due to the eoupling 45c
in headers 26 and eoupling 45a in headers 27, thus insuring a
given flow in the eonduits 28 of colleetor 11.
Couplings 45b in headers 26 present further resistance to
direet flow of the liquid in both headers and thus provides a
given flow in the eonduits 28 of eolleetors 12 and 13. Coupling
45b in headers 27 has a larger orifiee than eoupling 45a and pre-
sents less resistanee to total liquid flow in header 27. There-
fore, the liquid in the headers of eolleetors 11, 12 and 13 may
flow at substantially the same rate.
Coupling 45a in headers 26 and eoupling 45e in headers 27
further inerease the resistanee to flow in both headers, whieh
insures substantially uniform flow through the eonduits 28 of
eolleetor 16.
Coupling 45c in headers 27 has the largest orifiee 52c of
the eouplings in headers 27 to offer the least resistance to the
liquid entering headers 27 of eollectors 11-15.
The arrangement of the eoupling members 45a-45e in the
-- 8
array of ~ig. 9 presents a system analogous to headers 26
having a decreasing cross-sectional area from collector 11
to collector 16, and headers 27 having an increasing cross-
sectional area from collector 11 to collector 16. In this
manner the pressure of the liquid at each conduit 28 at its
junction with a header 26 is substantially constant resulting
in substantially uniform liquid flow through each conduit 28.
This results in lligher overall efficiency of the collector
array.
Bleed vent 53 can serve as either an air vent or as a
drain, depending on whether the vent is directed upwardly or
E do~nwardly. In array 10, exemplified in Fig. 9, the vents
of the coupling members between ~eaders 27 are shown directed
up~ardly and thus serve as air vents. The vents in coupling
members in lower headers 26 are directed downwardly, and can
serve as drains.
Baffle 52 shown in Figs. ~ and S is exemplified as being
across the center of the body 51. Baffle 52 may be si-tuated
any~here along passageway 51a. If baffle 52 is not directly
opposite bleed vent 53, opening 56 need not initially be pro-
vided in baffle 52.
Bleed vent 53 may be omitted from the coupling member.
In such event, opening 56 may similarly be omitted.
Baffle 52 may take any convenient shape. The baffle may
be angled with respect to fluid flow; it may have, for example,
a triangular cross-section, a smooth curve approximating a
venturi. A venturi may reduce fluid turbulence in the system.
The sizes and relative sizes of openings 52a, 52b and 52c
in the internal baffles 52 exemplified in Figs. 6, 7 and 8 are
3n by ~ay of example only. The particular size of the openings
is selected to balance fluid flow to each of the collectors
11 thrQugh 16 in tile array 10. If a longer array is required
in an installation having more collectors, more coupling mem-
bers 45 may be providecl between subsequen-t pairs of collec-
tors, and the orifices 52 in all of the coupling members must
be adjusted accordingly.
Coupling member 45 may be formed from a rigid material
sucll as brass, or alternatively may be formed from a resilient
milterial such as silicone.
Fig. 10 exemplifies a coupling member 57 formed from a
resilient material such as silicone. Member 57 includes a
body 58 which is substantially cylindrical except for a cir-
cumferential accordion fold 59 which will accommodate expan-
sion and contraction of the headers.
Body 58 defines a passageway 60 having baffle 61 extend-
ing thereacross. Member 57 is used in the same manner as
member 45, with varying amounts of baffle 61 being removed
depending on the location in the collector array, and the ends
e, ~ cO~ c~ ,7~s~
of body 58 receiving the ~*~ of the headers therein.
Fig. 11 schematically illustrates an array 70 of six
collectors 71 through 76, each having an inlet header 77 and
an outlet header 78. A plurality of heat-exchange conduits
79 extend between headers 77 and 78 in each collector. The
collectors are connected between an inlet manifold 80 and
an outlet manifold 81.
The inlet headers of collectors 71-76 are connected
to inlet manifold 8n, the headers of collectors 72 through
76 being connected through couplings 45e through 45a,
respectively. The upstream collector 71 is connected directly
to inlet manifold 80. Couplings 45d and 45e are similar to
- 10 -
tj
couplillg members 45a through 45c with successively larger
portions of baffle 52 being removed in couplings 45d and 45e.
Similarly, tile outlet headers o-f collectors 71-76 are
connected -to outlet manifold 81, the headers of collectors
71-75 being connected through coupling members 45a through
45e, respectively.
In the absence of coupling members 45a through 45e, with
the varying size baffles, the flow of fluid through the col-
lectors would not be balanced and the collectors towards the
center would be warmer.
In operation, the effect of the couplings 45a-45e
between manifold 8b and headers 77 is to present a substantially
uniform fluid pressure in the manifold 77 of all of the
collectors, and the couplings 45a-45e between headers 78 and
mallifold 81 act to balance the total flow of liquid through
each of the collectors. This arrangement effectively acts as
an inlet manifold of decreasing tapering cross-section from
upstream toward the downstream and an outlet manifold of
increasing flaring cross-section from the upstream toward the
downstream.
Alternately, the couplings may be installed in manifolds
80 and 81 to achieve a similar flow pattern.
Various arrangements of the balancing inserts may be
utilized. They need not be placed above one another as shown
in Fig. 9. For example, in an eight collector array9 three
inserts 45a, 45b and 45c may be used in the return header
between the first four collectors, and three inserts 45c, 45b,
and 45a between the last four collectors in the supply headers.
This arrangement provides an advantage in that the total
pressure drop across the entire array is less than for arrays
witll the inserts above one another in the return and supply
lleader connections as described in connection with Fig. 9.
The lower total pressure drop is desirable in that it
reduces the pumping energy required to move a given amount of
liquid through the collector.
It may thus be seen that the objects of the invention
set forth as well as ~hose made apparent from the foregoing
description are efficiently attained. While preferred
embodilllents of the invent-on have been set forth for purposes
of disclosure, modification to the disclosed embodiments of
the invention as well as other embodiments thereof may occur
to those skilled in the art. Accordingly, the appended claims
are intended to cover all embodiments of the invention and
modifications to the disclosed embodiments which do not
depart from the spirit and scope of the invention.
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